GUT INTRAMUCOSAL PH AS AN EARLY INDICATOR OF EFFECTIVENESS OF THERAPYFOR HEMORRHAGIC-SHOCK

Objective: To determine the value of intramucosal pH for evaluating th e effectiveness of treatment for hemorrhagic shock. Design: Randomized , controlled trial. Setting: University center, animal laboratory. Sub jects: Eighteen piglets, weighing 17 to 23 kg, Interventions: Anesthet ized animals were bled to a mean arterial pressure (MAP) of 40 to 50 m m Hg and a 70% reduction in cardiac output during a 1-hr period. This state was maintained for the next hour. The piglets were treated with crystalloid solution to restore cardiac output and MAP during the subs equent 80 mins of the experiment. Some animals were given vasoactive d rugs during volume therapy to modulate splanchnic perfusion and increa se the diversity of values of various variables. Measurements and Main results: Systemic hemodynamic and oxygen transport variables were mon itored. Tissue oxygen tensions were measured in the liver and abdomina l subcutaneous tissue layer. Gut intramucosal pH (pHi) was determined, using a balloon tonometer. The animals were divided into responders ( n = 9) and nonresponders (n = 9) according to whether pHi increased or decreased during resuscitation, Hemodynamic and oxygen transport vari ables improved in the group of responders. In the group of nonresponde rs, values decreased. Liver and subcutaneous oxygen tensions increased during the initial phase of resuscitation in both groups but decrease d after 30 mins in the nonresponder group. Conclusions: The change in pHi during the first hour of resuscitation could be used to divide ani mals treated uniformly from a hemodynamic point of view into two disti nct groups with seemingly different outcome, The minimally invasive me thod could be of value for early evaluation of the results of treatmen t of hemorrhagic shock.